Re: [net-next PATCH v7 2/4] net: phy: extend PHY package API to support multiple global address
From: Russell King (Oracle)
Date: Thu Dec 14 2023 - 18:54:50 EST
On Thu, Dec 14, 2023 at 05:54:51PM +0100, Christian Marangi wrote:
> What I don't like is the wrap check.
>
> But I wonder... Isn't it easier to have
>
> unsigned int addr = shared->base_addr + addr_offset;
>
> and check if >= PHY_MAC_ADDR?
>
> Everything is unsigned (so no negative case) and wrap is not possible as
> nothing is downcasted.
I'm afraid that I LOL'd at "wrap is not possible" ! Of course it's
possible. Here's an example:
shared->base_addr is 20
addr_offset is ~0 (or -1 casted to an unsigned int)
addr becomes 19
How about:
if (addr_offset >= PHY_MAX_ADDR)
return -EIO;
addr = shared->base_addr + addr_offset;
if (addr >= PHY_MAX_ADDR)
return -EIO;
and then we could keep 'addr' as u8.
Honestly, I have wondered why the mdio bus address is a signed int, but
never decided to do anything about it.
--
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